by Robert S. Katz, MD
This article is part of a series offering basic information about different types of arthritis and arthritis-related conditions.
Fibromyalgia is a chronic condition that causes pain all over the body, and it is among the most common and least understood of all the arthritis-related conditions. Although millions of Americans have it, there is a great deal that remains unknown about fibromyalgia and how it works in the body. This state of affairs has contributed to a general feeling of confusion surrounding the condition, among both doctors and patients. People with fibromyalgia may grow frustrated that their condition takes so long to diagnose and that so little seems to be known about it. They may feel that their symptoms are not taken as seriously as they should be by family members, friends, and even health-care professionals.
Although people have become more aware of fibromyalgia in recent years, the condition has actually been around for a long time. It used to be called fibrositis, a term introduced by William Gowers, MD, in 1904. But the “itis” in fibrositis signifies inflammation, and there is no evidence of inflammation in the muscles, joints, or other soft tissues in people with fibromyalgia, so in the 1970’s the term “fibromyalgia” was coined. “Fibro” comes from Dr. Gowers’s first (and incorrect) description of the cause of pain in fibrositis as residing in the fibrous tissue of the lower back. “Myalgia” means muscle pain.
The cause or causes of fibromyalgia are not well understood, and there are various theories as to how the condition brings about pain and other symptoms. Some researchers have speculated that a central nervous system (brain and spinal cord) disturbance is responsible; others place the disturbance in the muscles, tendons, and ligaments.
There is some evidence to support each position. By inserting a pressure gauge into muscles between the neck and shoulder, researchers have found that people with fibromyalgia have increased muscle tension, suggesting that the muscles are involved. Other studies using functional magnetic resonance imaging (MRI) of the brain have pointed to a problem with the way people sense pain. In one such study, both people with and people without fibromyalgia had similar brain areas activated on functional MRI when their thumbnail was (painfully) pressed. However, the brain centers of people with fibromyalgia lit up with a lot less pressure on the thumbnail than did those of people without fibromyalgia. This study suggests that fibromyalgia magnifies pain signals, making people more sensitive to pain. As one patient said to me recently, “If I get a pain in my hand, I feel like my whole hand is intensely painful, like a severe burn.”
There has also been research into how fibromyalgia changes the way the body processes pain. Studies of people with fibromyalgia have found pain signals going to the brain that are initiated, in part, by chemicals called substance P and glutamate. People with fibromyalgia have been found to have high levels of these chemicals. Researchers have also found that pain-inhibiting signals traveling from the brain to the body are brought on in part by serotonin and norepinephrine — substances that may be present in lower-than-normal levels in people with fibromyalgia.
It is difficult to say for certain how many people have fibromyalgia. According to the Arthritis Foundation, fibromyalgia is estimated to affect about 2% of Americans. In any case, fibromyalgia is thought to be greatly underdiagnosed. And while most people with fibromyalgia are women, men get fibromyalgia too, and their fibromyalgia may be especially likely to go undiagnosed. There also seems to be a genetic component to fibromyalgia; one study found that people who have close relatives with fibromyalgia are eight times more likely to develop the condition themselves. In addition, it is estimated that about one-fourth of people who have painful autoimmune conditions such as rheumatoid arthritis (RA) and lupus have fibromyalgia as well. In some cases, fibromyalgia seems to be related to a physical or emotional trauma in a person’s past though a recent study has suggested that the relationship between fibromyalgia and emotional trauma may not be as strong as has been believed.
The main symptom of fibromyalgia is pain. The intensity of the pain is usually quite significant. On a scale of 1 to 10, many people regularly rate their pain as a 7 or 8. The pain in fibromyalgia is widespread, occurring all over the body, although pain may occur in different parts of the body at different times.
Fatigue is another hallmark of fibromyalgia. People with the condition have difficulty sleeping. They find that they seldom fall into a deep sleep, wake up frequently during the night, and get up in the morning feeling unrefreshed.
Last Reviewed on May 7, 2012
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